1. Field of the Invention
The present invention relates to a method of constructing or reconstructing a blast furnace body using a ring block technique in which the blast furnace body is divided into a plurality of sections that are movable to and from the blast furnace hearth site.
A lifting transfer apparatus is provided for lifting and transferring the relevant furnace-body ring sections, or blocks.
The present invention is applicable to dismantling the existing blast furnace body, followed by efficiently either reconstructing another blast furnace body on the same hearth foundation, or newly constructing a blast furnace body on the same site.
2. Description of the Related Art
A conventional method of constructing a blast furnace body comprises the steps of (1) dividing a furnace body shell into small blocks, (2) assembling the furnace body shell at a blast-furnace assembly site by welding, (3) bringing a large number of staves, about 400 to 600 pieces, into the furnace one by one, (4) mounting the staves in predetermined positions, and (5) laying bricks in the furnace. Reconstruction of a blast furnace body in this manner has required a working period of 100 to 130 days.
On the other hand, a so-called furnace-body large ring block technique has been employed recently. This comprises the steps of (1) dismantling a furnace body into ring-shaped units (ring blocks) including a shell, staves and refractories all together, (2) disassembling, repairing and assembling the ring blocks at another site, (3) bringing each of the assembled ring blocks to a blast-furnace assembly site, and (4) connecting and assembling the ring blocks. This construction technique enables a blast furnace body to be reconstructed in a shorter period of not longer than 70 days.
Japanese Examined Patent Publication No. Sho 47-1846 discloses such a technique comprising the steps of (1) dividing a blast furnace into furnace-body ring blocks such as a hearth section, a bosh section, a shaft section, and a top-ring section, (2) constructing the divided furnace-body ring blocks on scaffolds each installed around the blast furnace, the scaffolds having a height that is equal to the height at which the corresponding ring block is to be assembled into the blast furnace, and (3) stacking the furnace-body ring blocks on the foundation of the blast furnace, one above another, while moving around the blast furnace horizontally for each step of stacking each ring block. This is done by using a movable scaffold, and then integrating all the ring blocks into an integral structure.
Also, Japanese Examined Patent Publication No. Sho 53-39322 discloses a technique comprising the steps of (1) dividing a blast furnace into several furnace-body ring blocks, and constructing those ring blocks at a site other than the foundation of the blast furnace, (2) assembling the divided furnace-body ring blocks one by one from the top section using a lifting technique which utilizes an associated tower provided on furnace-body support posts for construction of the blast furnace, and (3) fixing the hearth section on the foundation of the blast furnace along with a hearth base.
The conventional ring block techniques described above require working at a high altitude. The work involves assembling each of the ring blocks on a stand at a height up to about 7 meters above the ground surface. Such work at an elevated level not only necessarily pushes up the cost because of the expense of the stand, but requires improvement from the viewpoint of safety. Regardless of the size scales of the blast furnaces, the foundation of any blast furnace body usually requires an upper end height at about 4 to 6 meters. This is because the blast furnace is installed at a high level so that molten iron coming out of the tapping hole of the blast furnace will flow down through a sloped runner. The flowing steel is then introduced into a torpedo car, or a ladle or the like for carrying the molten iron for processing or use.
When dismantling or constructing or reconstructing a blast furnace using the furnace-body ring block technique, furnace-body ring blocks weighing about 1000 to 2000 tons are each moved from or onto the foundation of the furnace body at a level of about 7 meters above the ground surface for a blast furnace having a capacity of about 4000 to 5000 m3. Accordingly, horizontal beams each having a height of 1 to 2 meters are required for supporting the weight of the ring block. Further, when dismantling a blast furnace, the furnace-body ring blocks must be transported from a level of about 7 meters to a furnace-body disassembly site at a lower level. Conversely, when constructing a blast furnace, the furnace-body ring blocks, which have been assembled at a furnace-body ground assembly site at a lower level, must be raised up to a level of about 7 meters above the ground surface and then moved onto the supporting foundation of the furnace body.
A furnace-body carriage car having a height of about 1.5 meters and being able to raise and lower an upper surface is employed to transport the furnace-body ring block. Even with a packing beam mounted on the furnace-body carriage car for dispersion of the ring block weight, however, the total height is only about 3 meters and there still remains a level difference of 4 meters relative to the foundation of the furnace body. A load level-adjusting framework is required to absorb such a level difference. It is necessary to prepare the load level-adjusting framework in number corresponding to the numbers of divided ring blocks to be dismantled and the number of furnace-body ring blocks newly fabricated. Further, since the furnace-body ring blocks are moved on the load level-adjusting framework, the adjusting framework is required to have rigidity enough to endure the weight of each furnace-body ring block throughout its entire length. Thus, the furnace-body ring block technique is a method enabling a blast furnace to be reconstructed in a shorter period, but faces a difficulty in practical use because of the high production cost of the load level-adjusting framework.
To overcome the above-described problem, Japanese Unexamined Patent Publication No. Hei 10-102778 discloses a stationary lifting transfer apparatus for lifting and lowering a furnace-body ring block is installed in an appropriate place outside a blast furnace. When dismantling furnace-body ring blocks, each furnace-body ring block is moved onto a furnace-body carriage car and then transported to a stationary lifting transfer apparatus. A load level-adjusting framework in match with a level higher than the foundation of a blast furnace body is set on the furnace-body carriage car. Thereafter, the furnace-body ring block is lifted by the stationary lifting transfer apparatus, and the load level-adjusting framework is removed from the furnace-body carriage car. Subsequently, the furnace-body ring block is lowered and placed directly on the furnace-body carriage car. The furnace-body ring block is then transported onto a rest stand for storage. On the other hand, a newly fabricated furnace-body ring block is assembled at a ground assembly site at a low level, loaded on the furnace-body carriage car and then transported to the stationary lifting transfer apparatus. After that, the furnace-body ring block is lifted by the stationary lifting transfer apparatus to a level allowing the furnace-body ring block to be moved onto the foundation of the blast furnace body. Subsequently, the furnace-body ring block is loaded on the furnace-body carriage car on which the load level-adjusting framework is positioned, and then transported to the foundation of the blast furnace body.
The method of constructing a blast furnace body disclosed in the above-cited Japanese Unexamined Patent Publication No. Hei 10-102778 will be described below in more detail. In the disclosed method, a furnace-body carriage car having a structure as shown in FIGS. 1A and 1B of this application is employed. FIG. 1A is a side view and FIG. 1B is a front view. The furnace-body carriage car 1 includes a car body 2 having a rectangular flat upper surface. A multiplicity of wheels 3 with pneumatic tires are arranged under the car body 2, allowing the carriage car 1 to travel on the surface of the ground. A hydraulic lifting/lowering cylinder 4 is disposed over each axle so that the car body 2 is movable up and down. Further, each wheel 3 has a structure enabling the wheel to swing horizontally about a vertical axis 5. The structure for swinging the wheel 3 may be hydraulic, electric or mechanical (e.g., rack-and-pinion) mechanisms. Therefore, the direction in which the furnace-body carriage car 1 travels can be freely changed by swinging the wheels 3 as desired. There are two types of furnace-body carriage cars 1, i.e., the self-propelled type including a drive unit which enables the carriage car to travel back and forth, and the separately driven type having no drive unit. The furnace-body carriage cars 1 are longitudinally coupled with each other in use, and the total length can be adjusted by selecting the number of carriage cars coupled in tandem. Also, even a furnace-body ring block having a large width can be handled by arraying a plurality of furnace-body carriage cars side by side.
FIGS. 2A and 2B show a ring-block lifting transfer apparatus. FIG. 2A is a perspective view and FIG. 2B is a plan view. As shown in FIG. 2A, a stationary lifting transfer apparatus 6 is made up of four posts 7 fixedly installed on the ground and arranged at four corners of a rectangular zone as viewed from above, and two horizontal beams 8. As shown in FIG. 2B, the two horizontal beams 8 are each laid to extend between two of the four posts 7, having a longer span between them at top ends thereof. The horizontal beams 8 are positioned at a height in excess of 20 meters. This height is required to lift up the furnace-body ring block to such a level as allowing the ring block to be loaded on the furnace-body carriage car on which a load level-adjusting framework is set. On the two horizontal beams 8, lift jacks 9 are disposed at spaced positions in such a number as is required. In FIG. 2, a total of four lift jacks 9, i.e., two on each horizontal beam, are disposed. Also, as shown in FIG. 2, the four posts 7 are arranged at four corners of a rectangular zone as viewed from above. The horizontal spacing between two posts having a longer span therebetween is selected to be greater than the maximum diameter of the furnace-body ring blocks.
Specifically, the above horizontal spacing is set to a span of about 25 meters, for example, so that all the furnace-body ring blocks can be carried into the lifting transfer apparatus between the posts. The posts 7 having a shorter span between them are coupled with each other by a connecting structure 26 (FIG. 2B).
When constructing a blast furnace body by using furnace-body ring blocks newly fabricated, furnace-body ring blocks 11 (see FIGS. 3A-3D) are each assembled at a ground assembly site so as to lie on rest stands 10 having a height of about 3 meters (for example) above the ground surface, and are held in a standby mode. As shown in FIGS. 3A to 3D, the furnace-body ring blocks 11 have different shapes and sizes depending on the specified furnace design of the furnace body from the hearth to the top. When the furnace-body ring blocks 11 are held on standby, each ring block is supported on a rest stand 10 arranged at about ten positions, for example for dispersion of the ring block weight. Note that, in the ground assembly site, the needed procedures are performed for integrating a shell, staves, furnace-body bricks and stave connecting pipes, including even instrument units to be installed in the furnace body into an integral structure.
The furnace-body ring block 11 assembled at a ground assembly site is, as shown in FIG. 4, supported on a rest stand 10 arranged at predetermined support points. To transport the furnace-body ring block 11 to the construction site, the number of rest stands 10 supporting the ring block is reduced so that the ring block is supported by the rest stands at the smallest number of necessary points.
FIG. 5 shows an example in which the furnace-body ring block 11 is supported by the rest stands 10 at only four points.
Then, as shown in FIG. 6, four furnace-body carriage cars 1 are provided in the gaps below the furnace-body ring block 11 so as to lie side by side, spaced without interference with the rest stands 10. FIG. 6A is a front view looking from a position ahead in the direction of travel of the carriage cars, and FIG. 6B is a plan view. A packing beam 12 is placed on the furnace-body carriage car 1 in order to disperse the block weight over the entire length of the carriage car. At this time, the height of the furnace-body carriage car 1 is positioned lower than that of the rest stands 10. The car body 2 is raised with operation of the raising/lowering cylinders 4 shown in FIG. 1. The height of the furnace-body carriage car 1 is thereby increased to support the furnace-body ring block 11 through the packing beam 12. The rest stands 10 are then removed.
The furnace-body carriage cars 1, including the furnace-body ring block 11 loaded on it through the packing beam 12, are moved in the direction indicated by the arrow in FIG. 7, and then stopped at the installation position of the stationary lifting transfer apparatus 6 after passing under the horizontal beams 8 each extending between the posts 7 having the longer span there between. The furnace-body ring block 11 on the furnace-body carriage cars 1 at the stopped position is shown in FIG. 8A that is a front view looking from a position ahead in the direction of traveling of the carriage cars, and FIG. 8B that is a plan view. As shown in FIGS. 8A and 8B, the furnace-body ring block 11 on the furnace-body carriage cars 1 has hanger brackets 13 attached to a lower end of its side, and slings 24 suspending from the lift jacks 9 are connected to the hanger brackets 13. Then, as shown in FIG. 9, the lift jacks 9 are driven to hang up the furnace-body ring block 11, and the furnace-body carriage cars 1 are moved back in the direction of the arrow in FIG. 9. Subsequently, as shown in FIG. 10, the furnace-body ring block 11 is further lifted up until a lower surface of the furnace-body ring block 11 lies at a level of 7 meters or more above the ground surface. The furnace-body carriage cars 1 are then moved into a position below the furnace-body ring block 11. Now, a load level-adjusting framework 14 is set on each furnace-body carriage car 1 through the packing beam 12. The load level-adjusting framework 14 is made up of an adjusting framework body 27, rails 16 arranged on the adjusting framework body 27, and a movable platform 19 having support blocks 18 disposed on the rails 16.
Next, as shown in FIG. 11, the lift jacks 9 are driven reversely to lower the furnace-body ring block 11, whereby the furnace-body ring block 11 is loaded on the load level-adjusting frameworks 14 set on the furnace-body carriage cars
As shown in FIG. 12, the furnace-body ring block 11 on the load level-adjusting framework 14 positioned on the furnace-body carriage cars 1 is transported to a position near the foundation 15 of the blast furnace body, and the rails 16 provided on an upper surface of the load level-adjusting frameworks 14 are connected to rails 17 provided on the foundation 15 of the blast furnace body. The furnace-body ring block 11 on the movable platform 19 including the support blocks 18 disposed on the underside thereof is moved horizontally in the direction of the FIG. 12 arrow by the operation of drive cylinders 20. The mount position of each drive cylinders 20 can be changed such that the drive cylinder 20 are advanced step by step following the movement of the furnace-body ring block 11. In this way, the furnace-body ring block 11 is progressively moved from the rails 16 to the rails 17 and is finally positioned at the center of the foundation 15 of the blast furnace body.
Subsequently, the furnace-body ring block 11 is lifted up with slings 21 suspending from lift equipment (not shown) provided on posts of the blast furnace body. At this time, the furnace-body ring block 11 is lifted up to a level at which there is space enough to allow another furnace-body ring block to be next transported to move onto the foundation 15 of the blast furnace body, below the lifted-up furnace-body ring block 11. Also, the movable platform 19 is removed along with the support blocks 18 from the rails 17.
Likewise, the next furnace-body ring block 11 is moved into under the preceding lifted-up furnace-body ring block 11. These two upper and lower furnace-body ring blocks 11 are joined together and then further lifted up. The blast furnace body is completed by repeating the above-described process a number of times corresponding to the number of ring blocks newly fabricated, and integrating the stacked ring blocks into an integral structure on the foundation of the blast furnace body.
Since the newly fabricated furnace-body ring block 11 has a maximum weight of about 2000 tons, the ring blocks 11 are each assembled, as shown in FIG. 3, on a multiplicity of rest stands 10 arranged on the ground surface of the furnace-body ground assembly site. To load the assembled furnace-body ring block 11 on the furnace-body carriage cars 1, the rest stands 10 are required to have a height greater than that of the furnace-body carriage cars 1. Usually, unless the rest stands 10 have a height of 3 meters or more, the furnace-body carriage cars 1 cannot be brought under the furnace-body ring block 11. In other words, the process for assembling the furnace-body ring block 11 must be performed at an elevated level of 3 meters or more.
Further, to bring the furnace-body carriage cars 1 into a position under the rest stands 10 on which the furnace-body ring block 11 is placed, the number of rest stands 10 must be reduced to increase the span between the arranged rest stands so that the rest stands do not interfere with paths along which the furnace-body carriage car 1 is moved. At the same time, it is also required to determine the number and arrangement of the rest stands 10 necessary for supporting the furnace-body ring block 11, taking into account deformation of the furnace-body ring block 11 to avoid losing fabrication accuracy. Thus, there are various restrictions on the number and arrangement of the rest stands.
Moreover, the step of loading the furnace-body ring block 11 on the furnace-body carriage cars 1 takes substantial time. It further takes substantial time to set the load level-adjusting frameworks 14 between the furnace-body carriage cars 1 and the furnace-body ring block 11 after transporting the furnace-body ring block 11 to the stationary lifting transfer apparatus 6 together with the furnace-body carriage cars 1. In addition, the load level-adjusting framework must be set on and removed from the furnace-body carriage cars repeatedly whenever each furnace-body ring block is transported. For those reasons, the above-described method has been difficult to implement with good efficiency.
When dismantling the existing furnace body from a top section to a hearth section by dividing it into a plurality of furnace-body ring blocks, the operation is carried out in a reverse manner. In that case, the furnace-body ring block 11 placed on the load level-adjusting frameworks 14, which are set on the furnace-body carriage cars 1, is lifted up by the stationary lifting transfer apparatus 6. After removing the load level-adjusting frameworks 14, the furnace-body ring block 11 must be lowered to be loaded on the furnace-body carriage cars 1 again. Also, the dismantling operation is similarly troublesome because of restrictions imposed on the positions of the rest stands 10 and the necessity of due consideration for avoiding interference of the rest stands 10 with paths along which the furnace-body carriage cars 1 are moved.
Additionally, since the furnace-body ring blocks have different shapes and sizes, as shown in FIGS. 3A to 3D, the ring blocks are hung at different positions for each block. In other words, in the furnace-body lifting transfer apparatus wherein jacks for lifting the furnace-body ring block are fixed in position, the jacks cannot often be arranged in vertically aligned relation to the hanging points of the ring block. To install the ring block with good accuracy, the ring block must be kept in an exactly horizontal state. However, if the jacks are not arranged in vertically aligned relation to the hanging points of the ring block, a long time is required for horizontal level adjustment.
It has been therefore proposed to employ a hanger beam 31 shown in FIG. 13. More specifically, the hanger beam 31 has such a structure that block hanging positions 32 are movable and positions 33 at which the hanger beam 31 is hung by the jacks are fixed. Horizontal level adjustment of the ring block is facilitated by employing the hanger beam 31. However, because the lifting load is on the order of about 2000 tons and the load must be lifted up over a span of about 15 meters, a very high production cost is encountered. Moreover, each time the block hanging positions are changed, the hanger beam must be lifted up and down for position adjustment. Thus, even with the use of the hanger beam 31, the conventional method still needs time-consuming processing, a lot of labor and predetermined work sites, and is therefore troublesome.
An object of the present invention is to solve the problems of the related art disclosed in the above-cited Japanese Unexamined Patent Publication No. Hei 10-102778, and to provide a method of constructing a blast furnace body and a lifting transfer apparatus, which can improve the efficiency of the dismantling and assembling of the blast furnace body, done by dividing the furnace body from a top section to a hearth section into a plurality of furnace-body ring blocks.
More specifically, the present invention provides a method of constructing a blast furnace body, which is employed to dismantle and assemble the blast furnace body in a shorter period of time and at a lower cost, done by dividing the blast furnace body from a top section to a hearth section into a plurality of furnace-body ring blocks. The method comprises the steps of connecting a foundation of the blast furnace body to a carriage car having a loading level aligned with the foundation of the blast furnace body, and moving each of the furnace-body ring blocks there between; and moving each of the furnace-body ring blocks between the furnace-body carriage car and a furnace-body disassembly or ground assembly state by using a lifting transfer apparatus. The present invention also provides a method of constructing a blast furnace body, which is implemented by using a lifting transfer apparatus having a movable body and/or including a movable lifting mechanism.
The preferred form of the lifting transfer apparatus having a movable body comprises four posts arranged at four corners of a rectangular zone as viewed from above; two horizontal beams each laid out to extend between a pair of the posts having a longer span between the paired posts at top ends thereof; and a plurality of lift jacks disposed on each of the horizontal beams. Further, rectangular cut grooves that are open downward are formed at lower ends of the posts to extend along a horizontal line connecting centers of each pair of those posts that have a shorter span between the paired posts; a long rectangular carriage car having a flat upper surface able to freely raise and lower the upper surface and to change direction, and positioned to lie in the rectangular cut grooves formed at the lower ends of the each pair of posts, the carriage car being engaged with the each pair of posts when the upper surface of the carriage car is raised, and to be disengaged from the each pair of posts when the upper surface of the carriage car is lowered; and a lifting-transfer-apparatus carriage car including a load level-adjusting framework set thereon is allowed to move into a position at which a furnace-body ring block is hung by the lifting transfer apparatus to be loaded and unloaded.
On the other hand, in the lifting transfer apparatus including a movable lifting mechanism, the lifting mechanism comprises a lifting jack, and the lifting jack is slidable horizontally and is able to be always positioned in vertically aligned relation to a corresponding hanging point of the furnace-body ring block to be lifted up.